Electrical apparatus



Sept. 7 1926. 1,598,875

L. A. M. PHELAN Er Al.

ELECTRICAL APPARATUS Filed Nov. 24 1922 as mercury,

Patented Sept. 7, 1926.

UNITED 'STATES PA TENT OFFICE.

Lotus A. 1r. Hmmm nm cnnrronn norcnxiss, or nunon, wrsconsm; sam

HOTCHIJBS .ASSIGNOB T0 SAID PHELAN.

ELECTRICAL APPARATUS.

Application led November 24, 1922. Serial Ho. 603,027.

Our invention relates to electrical apparatus and it has special reference to electrical contact-making devices comprising s aced electrodes that are sealed into a close container and are adapted to be brought into electrical conducting relation with one another throu h the a nc of a movable conducting bo y, preablry a fluid Such as mercury, likewise disposed and which, on being tilted, is instrumental in performing the circuit-closing and circuitopening functions of the device.

More particularly our invention refers to an electrlcal contactar device of the character indicated above, which will operate for long periods of time and serve to make and break comparatively large a nounts of current without deterioration in any of its parts.

Our present invention pertains to an electrical contactor device, as described above, which, if desired, may comprise a c lindrical elongated tube, preferably in the oI'm-of a glass container, that serves to house electrodes and a body of conducting fluid such the latter being adapted to bridge the electrodes within the tube.A The tube is preferably disposed when installed, to occu y normally a osition neighboring on the librizontal and 1s suitably supported so that it may be tilted in either direction and thus allow the conducting fluid to flow into and out of circuit-making position at the expense of very little energy: The electrodes are sealed within the tube, and as shown in this particular instance, are adjacent to each other to form a cooperating pair. As shown, it will be noted that the leading-in wires to the electrodes enter the glass container at points spaced considerably distant or remote from the electrodes themselves.

A particular object of our present form of construction of contactor devices is that it enables the contact members to be spaced a considerable distance from the points where lthe leading-in wires are sealed in the glass container, thus avoiding the undesirable ei"-` fects due to the heat'o`f the arc at the contacts and its effects and adjacent glass.

A further object of this invention is to provide a particular spacing of the electrodesin relation to each other, to the container and to the body of conducting fluid upon the leading-in wires in said container a long life even when subjected to considerable quantities of stantial volta es.

Further objects will appear upon reference to the. following panylng drawings, in whi igure 1 is a vertical sectional view of one modification of device embodying our )invention Fig. 2 is al sectional view taken on line 2-2 of Fig. 1, looking in the direction of the arrows; y

Fig. 3 is an enlargeddetail view of the electrodes and mercury, showing the position of the mercury when about to come into circuit-closing position ;V

electric current at sub- Fig. 4 is another enlarged detail view of the electrodes and mercury, showing the 0- descrlption and accomsition of the mercury when in contact with both electrodes;

Fig. 5 is a view similar to that rin Fi s. 3 and 4, but showing the position of t e mercury when about to move to open circuit -position Fig. .6 is a form of electrode; A

Fig. 7 is a vertical sectional view of a modification of device embodying our invention, and

Fig. 8 is a sectional view taken on line 8-8.

of Fig. 7, looking in the direction of the arrows.

Referring to Figs. 1 and 2, the device preferably comprises in a general wayacylindrical, and elongated tube 11 made preferably of glass, housing a pair of cooperating electrodes or contact members 12 and 13, shown located at one end of the tube and which are spaced from each other and are adapted to be bridged by a body of mercury 14, which is likewise housedin the tube 11.

detail perspective view of one The'tube 11 when constructed isirst evacuated and then filled with a gas such as hydrogen, which is inert under the action of an electric arc in the presence of themercury and electrodes. This gas mfv be at substantially atmospheric preure and serves to minimize arcing and vaporizatlon of merproper direct ion,

cury in the tube .is well as deterioration of the tube. The absence of air and its oxy- .gen in the tube, eliminates all possibility of oxidation of the mercury and electrodes.

It will be observed from the drawings that if the tube 11 should be tilted in the the body of mercury 14 will flow toward the electrodes 12v and 13, thus bridging the electrodes, thereby placing them into electrical conducting! relation with each other. The electrodes 12 and 13 are made of suitablemateral, such as pure iron, or other conducting materials that do not suffer deterioration under the conditions obtaining` and are supported respectively on connecting leads 15 and 16, also preferably composed of a similar metal. The use of iron is desirable in that this metal does not become amalgamated. The leads 15 and 16 may be integrally formed with electrodes 12 and 13, or if desired, the cores of the leads maybe made separate as at l in Fig. 6 and also of metals other than those named above, in which latter case they should be covered or plated with a sleeve composed of one of the pure metals named above, in order to avoid any interaction of the mercury or vapor in the tube with the core or any impurities therein.

AThe leads 15 and 16 are supported respectively on glass shanks 17 and 18, which extend down from the end walls of and are formed integrally with the glass chambers -19 and 20, respectively, at the ends of the tube 11. Leading-in Wires 21 and 22 made of Dumet wire. because of its desirable eX- pansive properties and its tendency to unite with `:rlass when sealed into glass` provide means for connecting the leads 15 and 16, respectively, in an external electrical circuit. The leading-in Wires are joined to the leads 15 and 16 at joints 2? and 24, respectively, at the inner'end of and referably slightly Within the glass Shanks 1i) and 18 and hence the Dumet Wire is at no place exposed in the interior of the tube. The joints 23 and 24 are preferably very near the ends of the glass shanks 17 and 18 so that the expansion or contraction of the leads 15 and 16 will not unnecessarily strain the glass. The leadingin wires 21 and 22 may be connected, respectively, to flexible leads 25 and 26, or to other suitable connecting membersot the exterior circuits.

The tube l1 is evacuated, filled with hydrogen and sealed off by means of a tip 27.

The seals to the Dumet Wires 2l and 22 and glass sbanlts 17 and 1S are located Yat the extreme ends of the tube in the modification of Figs. 1 and 2 and at a distance from the electrodes. The glass chambers 19 and 20 serve t-he double purpose of furnishing a larger radiating surface and of enclosing and supporting the glass Shanks 17 and 18, which can thus ll'iernade of sufficient length to rigidly support and seal the wires 21V and 22 and still not extend into the main portion of the tube. The glass shanks in former structures .have been constructed to ext/end into the main portion of the tube where they tend to interfere with the free flowing of the mercury and also are exposed to the heat of the arc at the contacts. Our present type of construction also permits the use of leads 15 and 16 of considerable length. Leads of this length permit the greater part of the heat of arcing to be radiated before it can possibly be conducted to the glass shanks 17 and 18. The small amount of heat that is conducted to these Shanks is not subject to any rapid fluctuations and is insuiiicient to result in any damage to the glass.

It will be observed that the supporting Shanks 17 and 18 and the glass chambers 19 and 20 in this structure are located at the upper side of the tube at points well out of the way of the mercury 14 and the arcing at the electrodes 12 and 13, so that in the normal operation of the tube the mercury does not come in contact with the surfaces of these glass parts and thus all possibility of the g'athering,r of a conducting coatin on lthese parts is avoided or greatly minimized.

A form of the electrode that may be used at 12 and 13 is shown in detail in Fig. 6. It will be noted that the electrode comprises a considerable volume of material. The object of this larger volume of material in comparisonto the size of the lead wires is for the purpose of absorbing as much as possible of the heat Igenerated at. the elec trodes, due to the arcmg that. occurs when the circuit is open or closed. A further object of these large electrodes is to insure ample contact area. It will be noted in Fig. 6 that the end of the electrode is slightly rounded at 12, The use of dat surfaces on these electrodes has been avoided in order to avoid undesirable sticking of the mercury to the electrode. It hasV been found that where plain surfaces have been used on the electrodes that the mercury has a great tendency to stick to such surfaces after use devices for a short time. The rounded surfaces tend to avoid the tendency of the mercury to create if vacuum between itself and the electrode when the two are being se arated and that henceV the avoidance of t is vacuum does away with the difficulty of sticking. When the tube is tilted to only a relatively slight angle, the flow of the mercury can be very easily retarded or stopped. It has even been found that a slight contamination of the mercury by any impurities will render the mercury sutliciently slu gish to prsvent its proper operation at suc slight angles.

It is very desirable that the electrode be made in substantially the cylindrical form shown since the rounded surfaces offer very' of theV lub nuocereA .little resistance to the natural llow of the mercury and valso avoid the creation of troublesome vacuum spaces which occur be,

tween `llowing mercury and llat metallic l surfaces and result in checking 4the flow l tion thanthe electrode 12.

14 will slowlyilow toward 25. trede will lbecome wetted vby the mereu 3 'tion marasma v ldeep tovalter its shape to touch It willlbel noted that the electrode 13 is` placed nearer lthe center or mid-portion of' the tube 11 and at aslightl greater elevat will be noted that both of `the electrodes are placed in a position such thatnopart of the glass container is directly exposedto thearci Ther movementof the mercury iii the process. of makiugiand breaking the circuit will now be out edA in order to bring out clearly -the advanta o f-this particular 'tiont te31E thrill ectijodes the tiile `is slowly in proper on, e merc the electrodeulry, theelectrode 13 being in `a slightly plane is (not lirst touched by the mercury 14, the 12p-.the

y of

surfacegof the elecand vthe consequentcapillary action w draw, the merc around t e lower poi-- -tion et the eylin 'cal surface ofthe elec-y trode as 3,44 and 5. The o mercuryl at this Assamese@ a pears in orthebod reet 1L "htlyfmore the A athe en of the container cause ow of the mercuryto- "ptosomeextentandthe'body 'tion ofA e body y circuitis closed in slightly exaggerated form in for the desirable results will be out ed .in the following aragralph.

When the tu is ti ted in the reverse direction for. opening the circuit the body of mercury 14 assumes the shape shown in Fig. 5. It be noted that the surface tension on theY mercury tends to cause the body of mercury to stretch or becoiiieelongated and thus remain in contact with the electrode 12 slightly longer than it otherhi her llows around.

reviousc'ontact.

mercury a p es action n -theo. of ov dra-tion of the device -w ch' is bellved topebe res lisibleA Jwise would.` When the tube becomes sui, ciently tilted, however, the surface tension is interrupted and the circuit is broken at this int; Afterthe mercury leaves the electr e 12, its surface l be resumedvwith a sna action and the surface will then be sullidiently distant from the electrode to cut oli any possibility of further arcing. However, f-large currents are carried a sl' bt arc will occur at the electrode 12 j as the circuit becomes broken Vand this arc will, in someeases, be suiiicient to volatilize a,Y l the body ofmercury I14 and will also volatilize any mereury'which would otherwise remainY on and Serve to kee the electrode 12 in a Awetted condition. Ila'hls trede 12 exposed softhat it is undesirable to permit another arc to'occur. at` this point.

until the surface is again wettedwith mer- A n metallic Vbody in the presence of heated gases is subject to4 deterioration by molecular bombardment. ItV

will be understood that Aany volatili'zation of small amounts of mercury .in the tube isnot particularly undesirable and such action is preferable to any possiblev deterior-l ation of; the bare electrode surfaces. For these Yreasons therefore the circuit Ais made or completed at the electrode 13 and in- Witlr such a cycle of o tions, the areing if any, always occurs tween the body of mercury'lt ,and that 'one of the electrodes 12 or lil which has last been wetted by conta'ctwith the body ofmercury. After'ea-ch arcingoc'cura the electrode at that point has an opportunity to become covered with me to replace that which has been volati bdy of conductin tluid in connection -with the electrodes. is argely responsible for the success of this form of lcontacter n `circuits where some other types ofA me contactors have failed to oper ate' satisfactorily.

t In the modification sliown'in Figs. 7 and 8, the glass chambers 28 and 29 are both tension will again small amount of:

` will 4leave the bare and unwetted surfaceof the elecbefore another arc can Aoccur at this i point. Itis believed that method of using a moving will terrupted or broken at the electrode 12.

located at considerable distance. from the regionof the electrodes. The glass chainy bers in this modification l are located at points adjacent the center of the tube for a rticular purpose.A The modification. of igs. 1 ccd2 ises with apparatus w erein the tube is tilted ally designed for use only to a comparatively slight angle, l'wlieret as the modification of'Figs. 7 and 8 is cstally designed for` use in apparatus such as thatk in which the tube is tilted., to a ve large angle for example in the neigh- .boliv'hood of '90.7 In the latter form if the chamber 29 werelocated at the end of the tubethis would result in a great enlargethe wheat-regalati to i large angle. This displaceme'n @of the Imercury would -result @a i Vin a disconnection of the circuit to the inner electrode 30fnless an excessive amount of" mercury Werefused. It ivill'also he noted that in the modification of Figs. 7 and 8 that the leads to both electrodes 30 and 31 extend for a considerable distance away from the. region of the electrodes. With this structure the seals at both of the leads are at, a safe distance fromthe heat at the elec, trodes. This form cf tube therefore is par ticularly adapted to operate with large currents and t'o operate satisfactorily even though tilted to a great angle.V The electrode 30 is shown tilted a slight amount from the vertical position in orderithat itV may be placed within a tube of the usual diameter and still leave room for the lead to the other electrode 3l. It will be noted that the velectrode 30 in this-modification is also positioned a slight amount above the level of the electrode 31 for the reason above pointed out in connection with the modification of Figs. 1 and 2..

The forms of contactors as above de!" scribed form a very reliable means for'controlling electrical circuits carryin substantial currents` at comparatively hig voltages without deterioration. Such a device obviously has a great many advantages over any former t e of switching mechanism, sinceY very litt e energy is required to tilt thev tube into an out of circuit-making position and at the same time the device is designed to be placed directly in series with the electrical apparatus controlled thereby.

While "we have shown and described several embodiments of our invention, it is to be understood that man modificationsy may be Amade therein wit out departn from the irit and sco of the ap end claims, an wedesiret at only suc limitations shall be imposed upon our invention as are s ecilically pointed out in the claims and suc as are required by the prior art. Having thus described our invention, what we claim as new and desire to secure by Letters Patent in the United States, is

1. An electrical contacter comprising an hermetically sealed container, electrodes of substantial and concentrated mass contained therein' that are spaced remotely from the container walls, a movable ,contact engaging the lower inner surface of said container and adapted to contact with said electrodes at predetermined times, said container bein provided with aced outwardly expande chambers, leads or said electrodes entering said container through said chambers an being hermetically sealed therein remotely from said movable contact, said electrodes ,"formed of a substantially 'atected by said body of co fthe presence of heat.

and from the heat of the arcing that may obtain at said electrodes.

2. An electrical contacter comprising an liermetically sealed container, electrodes of substantial contact-making area and of concentrated mass disposed therein that are spaced trom the container walls, a body of conducting uid engaging the lower surface or said container and4 adapted to contact with said electrodes at predetermined times, said container being provided on one of its sides with at least one outwardly expanded chamber, a leading-'ui Wire for one of said electrodes Yentering said containerthrough said outwardly expanded chamber and being hermeticall sealed therein at a point remote from t e associated electrode, the exterior. of said. electrodes and the said leadlng-in Wire within said container being made of material that is substantially nondeteriorating under the conditions obtaining within said container.

3. An electrical cont-actor comprising a hermetically sealed container, electrodes con' tained therein adjacent a longitudinall axis thereof and spaced from the containerwalls, a body of conducting-fluid engaging the lower inner surface of said.container and contacting with said electrodes at fredetermined times, leads for said electrodes entering said container through outwardly expanded extensions on the upper side and sealed therein at points remote fromsaid electrodes, the exterior of said electrodesand of said leads within said container being ure metal unucting fluid in ii 4. An electrical contacter comprising a Hermetieally sealedA container, electrodes con tained therein and spaced from the container valls, albody of mercur for contacting withl said electrodes at'pre etermin'ed times, an outwardly expanded extension chamber on the upper side of said containerz 'a lead for one of said electrodes entering sald container through said chamber and sealed in a wall of saidichamber remote from the region of said body of mercury and said electrodes.

5. An electrical contacter comprising a hermetically sealed container, electrodes contained therein and spaced from the container Y wal-ls, a movable contactffor contacting with said electrodes at piedetermined times, outwardly expanded extension chambers on the upper side of said container at spaced points, leads for said electrodes entering said container through said chambers and sealed in walls of said charn'bers remote from the region of said electrodes.

6. An electrical contact making device comprising a hermetically sealed container provided on the upper side thereof with at least one integral outwardly expanded extension, cooperating electrodes in said container and spaced from the Walls thereof, leadingin wires therefor that are sealed in the 4walls of said container,""ine otV said leading-in Wires being sealed in tlie remote wall of said extension, and a bod of conducting Huid engaging the inner liiwer surface of said container which serves to contact with said electrodes. l

7. An electrical contact making device coin ,rising a hcrniclically scaled container prmiblcd at the upper side thereof with spacci integral outwardly expanded extensions; electrodes in said container spaced from the walls thereof, leading-in wires therefor that are severally sealedin the remote walls of said extensions and a body of conductinv fluid engaging-te innerlower surface o said container which serves to contact with said electrodes.

8. An electrical 4switch comprising a licrmctically sealed container, a contact mak ing electrode contained therein and spaced from the container walls, a movable body of conducting lit uid for contacting with said electrode at predetermined times, a subst-antially vertically 'extending with said container, a lead r-in wire for said electrode entering said container through and sealed in said shank remotely vfrom said electrode, and an outwardly expanded extension chamberon the upper side of said containcipin a position spaced from said electrode and from the normal path of 1' said body of liquid. substantially all of said shank being contained within said extension chamber.

9. A tiltable electrical contacter comprising an elongated hermetically sealed glass container, spaced electrodes positioned in one end thereof and spaced from thetwalls of said container, a body of conducting liquid free to tiow from end to end Qi sai container into or out of bridging relation with said electrodes at predetermined times, integrally formed outwardly expanded extension chambers 'on a side of said container in positions widely spaced from the normal path of fiow of said mercury, inwardly extendin integral Shanks in said chambers, leads or said electrodes entering said container through, and sealed in said Shanks at remote points from said electrodes.

10. An electrical contacter comprising a sealed container, an electrode contained thenein adjacent one end Wall thereof, a second electrode contained therein in prox imity of and normally slightly above said first named electrode but at a greater distance from said end wall, both of said electrodes being spaced from' the container walls, and a body of conducting liquid free to How along the bottom of said container into and out of bridging relation with said electrodes at pre-determined times.

Shank integral 11. An electrical contacter comprising a sealed container, an electrode contained therein adjacent one end wall thereof, a second electrode contained therein in proximity of and slightly above said trst named electrode but ata greater distance from said end Wall, a body of ronductiii liquid at the bottom of said container for ridging said electrodes at predetermined times, and a lead forsaid second named electrode entering said con-- tainer and sealed therein at a point remote from said electrodes.

12. A tiltablc electrical contactor comprising a hermetically sealed elon ated glass container, electrodes contained erein and spaced from `the walls thereof, a body of mercury for lcontacting with said electrodes, supporting and connecting leads ex sed interiorly of said container for said e ectrodes and com d of a metal substantially unaffected y said mercury in the presence of an electric arc and heat, outwardly expanded extension chambers located at spaced oints remote from said electrodes on sai containertand remote from the normal path of ,flow of said body of mercury, and inwardly extending integral glass Shanks at the outer ends of said extension chambers, 'said leads entering said container through said Shanks and said extension chambers remote from said electrode.

13. A tiltable electrical contacter comprising a hermetically sealed elongated glass container, electrodes contained therein adjacent one end thereof and spaced from the walls of said container a body of mercury for contacting with said electrodes at predetermined times supporting and connecting leads for sai electrodes composed of a metal substantially unaffected by' said mer .cury in the presence of heat and an electric arc, and outwardly expanded extension chambers located at s aced points-on said container and remote from the normal path of flow of said body of mercury, said leads .entering 4said container by being sealedl through the up er central portions of said extension chain rs whereb said seals are located remotely from saidY electrodes 'and said body of mercury.

14. A tiltable electrical switch comprisv ing a. hermeticaliy sealed container, coo rating contact making electrodes contained therein and spaced from the Walls thereof, a movable body of conducting liquid for contacting with said electrodes at predetermined times, inwardl substantially verticali extending shanl-yts integrally formed wit said container, leading-in Wires for said electrodes severally entering said con tainer through and sealed in said Shanks, and spaced outwardly expfinded extension chambers on said continuer in positions widely spaced from said electrodes and from the normal path of said body of liquid, said Shanks being Iargcly contained within said extension chambera 1 15. An electrical switch comprising a hermetically sealed glass container, cooperating contact making electrodesl therein, a movable body of conducting liquid' for contacting with said electrodes atl pre-determined times, an atmosphere inl saidf'container comprising an arc suppressing gaps,

rods for supporting said electrodes at posi-- respect to each other and inthe presence of,

an electrical aro.

16. An electrical contactor comprising an hermetically sealed container, Vspacedv electrodes of substantial and concentrated mass contained therein and spaced from' the container/walls, a movable contact for contacting with said electrodes, leadi in wires hermetically sealed in the Wall o said container, and'su ports for said electrodes connected to sai Aleading-in wires,l the points of connection between said sup orts and their respective leading-in Wires in embedded in the container walll to preclu e exposure of said leading-in wires within the container.

f17. An electrical contacter comprising ancontacting\wzith said electrode, a leading! 1n hermetically sealed in the wall of said container, and a support for said electrode for holding it spaced from the oontainer wall, said support being connected to said leading-in wire andthe point of connection between said support and said leading-in wire being embedded in the container vvall to vpreclude e osure of said leadingin wire interiorly o said container.

18. An electrical contacter comprising an hermetically sealed containe'r, an electrode contained therein and spaced from the container Wall, a movable contact housed in Said container for contacting with said electrode, an outwardly expanded extension chamber formed on a side of the container remote from the path of said movable contacta leading-in wire entering said container through said extension chamber and hermeticaliy sealed therein remote from said electrode and said movable contact, and a support for said electrode connected to said leading-in Wire, the point of connection between said support and said leading-in Wire bein embedded in the container wall to prec ude exposure of said leading-inwire within said container.

In Witness whereof, We have hereunto subscribed our names.

Loms A. M. PHELAN. CLIFFORD HoToHKIss.

shanks being largely contained within said in wires attached adjacent the inner surface of the glass walls to said rods andextending outside the container, said liquid said atmosphere of gas and the surfaces o said electrodes and rods being formed of materials, which are substantially inert with respect to each other and inthe presence ofV an electrical arc.

16. An electrical contactor comprising an hermetically sealed container, spaced electrodes of'substantial and concentrated mass contained therein and spaced from the container'walls, a movable contact for contact- -ing with said electrodes, leadin -in wires hermetically sealed the wall o said container, andsu ports for said electrodes connected to sai leading-in wires, the points of connection between said supprts and their respective leading-in wires in embedded in the container Vwall to preclu e exposure of said leading-in wires within the container.

said electrodes at posi essere f1?. An electrical contacter comprising ancontactth said. electrode, a leading? in wire hermetically sealed in the wall of said container and a support for said electrode for hol dgit spaced from the container wall, sai support being connected to said leading-in wire andthe point of connection between said su ort and said leading-in wire being embe filed in the coritainer wall to preclude exposure of said leadingin wire interiorl'y o said container.

18. An electrical contactor comprising an hermeticall sealed containe'r, an electrode contained t erein and spaced from the container wall, a movable contact housed in said container for contactin with said electrode, an outwardly expande extension chamber formed on a side of the container remote from the path of said movable contact,.a leadinin Wire entering said container throng said extension chamber and hermetically sealed therein remote from said electrode and said movabley contact, and a sup ort for said electrode connected to said lea ing-in wire, the point o'f connection between sad su port and said leading-in wire bein embed ed in the container wall to prec ude exposure of said leading-in wire within said container.

In witness whereof, we have hereunto subscribed our names.

Louis is. M. PHELAN. CLIFFORD HoTcHKIss.

' certificaaof chi-ration.

lt is hereby certified that in Letters Patent No. 1,598,875, granted September 7, v 1926, upon the application of Louis A. M. Phelan and Clifford Hotchkiss, of Beloit, Wisconsin, for an'improvementin Electrical Apparatus, errors p. pear in the printed specification` requiring correction as lfollcws 1 Page 4, line 93, c aim 3, strike for read with these corrections-therein that the case-iii the Patent Oice.

and adapted to contact; wprd electrode read electrodes; and that the said ge 5 line 96 clai1n'12 tters Patentshould-hdl same may eonformto'therecord of the Sigmund sealed this 2d day fsb-femmes. JD. was., Y

, WMLKINAN, am omwpfrm.

'zel

Certificate of Correction.

1t is hereby certified that in Letters Patent No4 1,598,875, grant/Bd September 7, 1926, upontlie application of Louis A. M. Phelan and Clifford Hotchkiss, of Beloit, Wisconsin, for an improvementA in Electrical Apparatus, errors appear in the printed specification requiring correction as follows: Page 4, line 93, claim 3, strike out` he word contacting and insert adapted to contact,- age 5, line 96, claim 12, for e wprd electrode read electrodes: and that the sai tters Patent should be read with these corrections therein that the same may conform to the reoord of the casein the Patent Oce.

Signed and sealed this 2d day of November, A. D. 19

` W'M. A. KINNAN,

Acting Commissioner of Pamta. 

